The aim of this project is to determine whether a relationship exists between episodes of spontaneous nonsustained ventricular tachycardia (defined as runs of ventricular tachycardia at rates >100 bpm, lasting from 3 beats to up to 30 seconds, terminating spontaneously) and sustained monomorphic ventricular tachycardias occurring after acute myocardial infarction. The results may serve to redirect investigative efforts either towards or away from the use of ambulatory electrocardiographic monitoring, both as a research & clinical tool.